Melt crystallization Brennan-Koppers crystal purifier

A fourth process is the Brennan-Koppers crystal purifier (Brennan 1982). The apparatus has wall filters like the Phillips column and a melter at the top like the Kureha process. The crystals move up due to the movement of the liquid. The crystal bed is held compact with a rotating top plate, which is called a harvester. Some crystals at the top of the bed are collected (scraped off) and some openings thereafter permit these crystals to enter the melting zone at an adjustable rate. Some of the remolten liquid flows back through the harvester and washes the crystals in the bed. The residue leaves the apparatus by the filters. Details are given in the patent cited above. 

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